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Motorcycle Repair/bike stalls when i give it gas

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Question
Hi
I have a 1985 Honda shadow vt1100 that stalls every time i give it gas from idle also if i let off the gas it will stall. It has new plugs and I have just had the carbs rebuilt. It will idle no problem.

Answer
Nakaya,  You might want to check the ignition coil's primary resistance and the spark plug caps for signs of an open circuit or high resistance.

Assuming that the carburetors were rebuilt with OEM parts and cleaned thoroughly, the only leftover issues could be a damaged carburetor slide diaphragm.

http://www.cmsnl.com/honda-vt1100c-shadow-1100-1985-usa_model799/partslist/E++20  #12

Additionally, if you have altered the intake system or the mufflers, the original jetting was set up very lean to meet emission standards which can go out of specifications if you alter the intake/exhaust systems.

Try putting the choke on a little bit to see if it takes throttle more easily. If so, then there is either an air leak at the intake manifolds or the fuel jetting is too lean, assuming other components are working correctly.

IF the air cut valve diaphragm has failed or there are other vacuum leaks, you will get similar symptoms.
http://www.cmsnl.com/honda-vt1100c-shadow-1100-1985-usa_model799/partslist/E++20  #4

I would also check the ignition coils for matching primary resistance values. If one is way off from the other, you will have misfiring and part-throttle performance issues, too.

Bill Silver  

Motorcycle Repair

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Bill Silver

Expertise

Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.

Experience

I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

Organizations
VJMC (Vintage Japanese Motorcycle Club) of North America

Publications
VJMC newsletter, as editor for two years and as contributing editor currently.

Education/Credentials
3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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